Justification:Melocactus conoideus has a very small range (extent of occurrence less than 100 km2), it is known from one location, and the population is in continual decline. Part of the population is protected, however the rest are quickly disappearing. This cactus is therefore listed as Critically Endangered.

There are several hundred plants, however there have been significant declines, with the exception of a fenced area where a couple of hundred individuals can be found. Some subpopulations have recovered well after quarrying for gravel was halted.

In 1989 M. conoideus was close to extinction at the type locality in the Serra do Periperi above Vitória da Conquista, Bahia, where it is sympatric with the widespread M. concinnus. However, from the original locality another adjacent area of similar habitat could be seen and subsequently Brazilian cactus enthusiasts have confirmed that a healthy extension of the population exists. This area is more distant from the BR 116 highway and is now officially protected, although this has so far failed to halt gravel extraction.

The population found in 2002, which was very healthy, has now been depleted because quarrying was moved to this location, which is ca 2 km from the type locality.

The major threats for this species are habitat loss due to quarrying and urbanization, specifically the growth of the city of Victória da Conquista. The species survival in the wild is severely threatened by extraction of the quartz gravel in which it grows, and was formerly impacted by commercial collection for the European horticultural market.